Conventionally, as a pneumatic tire having land portions partitioned by a plurality of circumferential grooves, suggested are various tires having defined outlines of the land portions in a tread widthwise cross sectional view, such that a ground contact area of the land portion becomes a specific shape when the tire contacts the ground.
For example, in PTL 1, suggested is a pneumatic tire having a center rib extending in a tread circumferential direction, which is partitioned between a pair of main grooves disposed on a tread portion, wherein: a cross sectional profile line of a tread surface of the center rib crosses a virtual tread profile line which smoothly connects a tread surface inclusive of both ground contact edges except for the center rib, a tire axial central portion of the center lib forms a smooth convex shape toward a tire radial outer side, and protrudes from the virtual tread profile line toward the tire radial outer side, and at least one edge portion of the center rib caves in on a tire radial side inner than the virtual tread profile line. According to this tire, it is possible to achieve both the steering stability and the hydroplaning preventing performance at a high degree.